1. Field of the Invention
The present invention relates to a short-range wireless communication systems, and more particularly, to an apparatus and method that can control a transmitted/received voice signal between a Bluetooth headset and a portable terminal using dual microphones of the Bluetooth headset.
2. Description of the Related Art
In general, a Bluetooth network refers to a piconet having one master terminal and a plurality of slave terminals that are connected to each other via the Bluetooth protocol. In one piconet, the plurality of slave terminals may receive data from one master terminal. Multiple piconets may form a Bluetooth network, which is referred to as a scatternet.
With the spread of portable terminals, a user receives data on their portable terminal from another user and transmits the data to another user's portable terminal via the Bluetooth protocol. Also, users can perform telephone communication and listen to music in MP3 format using a wireless Bluetooth headset.
Since the Bluetooth headset provides portability convenience and allows a user to perform a voice call while it performs wireless Bluetooth communications to the portable terminal, the spread of the Bluetooth headset is gradually increasing.
Such a conventional Bluetooth headset performs a voice call as follows. First when a call is initiated, a user talks to a microphone installed on the Bluetooth headset. Then, the Bluetooth headset inputs a voice signal through the microphone and then transmits it to a portable terminal via the Bluetooth communication. The portable terminal transmits the inputted voice signal to a portable terminal of another caller in wireless communication.
However, the conventional Bluetooth headset allows ambient noise along with the voice signal to be input through the microphone, transmitting both to the opposite caller. That is, the noise in the conventional Bluetooth headset decreases the intelligibility of the voice call between the portable terminals.
To solve the problem, a Bluetooth headset has been recently developed, to which a bone conduction microphone is applied. The bone conduction microphone converts vibrations, transmitted through a user's bone, into a voice signal and transmits the voice signal to the Bluetooth headset. The bone conduction microphone can be effective in environments with high levels of ambient noise.
However, the bone conduction microphone is has disadvantages in that it attenuates a voice signal in an environment with relatively low ambient noise and decreases the tone and quality of the voice, compared with those of a general microphone that receives a voice signal transmitted through the air. That is, the Bluetooth microphone makes it difficult for an opposite caller to clearly hear the transmitted voice signals due to ambient noise. However, although the conventional bone conduction microphone reduces the ambient noise, it also decreases the tone and quality of a voice in a quiet environment compared with a general microphone.
The conventional Bluetooth headset also has disadvantages in that it makes it difficult for a user performing a voice call to clearly hear the opposite user's voice transmitted through a speaker due to the ambient noise. As a result, the user must manually adjust the volume of the speaker to optimally hear the voice in view of the ambient noise.